Renewable indicator for cartridge fuses



Feb. 27, 1923.

1,446,556. I. B. GLOWACKI.

RENEWABLE INDICATOR FOR CARTRIDGE FUSES. FILED MAR. I8, 192a.

mam/m0 INSULATION Patented Feb. 27, 1 923.

UNITED STATES PATENT OFFICE.

JOHN B. sLowAoKI, or CHICAGO, ILLINOIS.

RENEWABLE INDICATOR FOR CARTRIDGE rusns.

Application filed March 18, 1920. Serial No. 366,864.

To allwhom it may concern: Figure 4 is a section on line 44 of Fig- Beit known that I, J OHN B. GLOWAOKI, a ure 3. 55

subject ofthe Republic of Poland, having declared my intention to becomea citizen of the United States, and aresident of the city of Chicagofinthecounty of Cook and State of Illinois, have invented certain new anduseful Improvements in a Renewable Indicator for Cartridge Fuses; and Ido hereby declare that the following is a full, clear, and exactdescription of the same, reference being bad to the accompanyingdrawings, and to the numerals of reference marked thereon, which form apart of this specifica- 5 tion.

This invention relates to a renewable in dicator for encased fuses. Inmany cases where electric circuits are being used only intermittently itis difficult to determine whether or not the fuses in said circuit arein good condition. When a number of circuits are 'used it is alsodifficult to ascertain which of said circuits is out of'order through afuse beingburned out. This is particularly true when the fibre casecartridge fuses are used, there being no means of ascertaining by anexternal examination whether or not the fusible metal inside thecartridge is destroyed.

It is an important object of this invention to provide a removableindicator for encased fuses whereby a burned out fuse may be easilylocated. o

Other and further important objects of this invention will be apparentfrom the disclosures in the specification and the accompanying drawings.

The invention (in a preferred form) is illustrated in the drawings andhereinafter more fully described. a

On the drawings:

Figure 1 is a longitudinal section of a cartridge fuse with knifecontacts showing the indicatng device of this invention secured in theinsulating casing of said cartridge fuse.

Flgure 2 is a longitudinal section taken through a cartridge fuse havingclip contacts showing the indicating device of this invention secured inthe outer insulating casingthereof.

Figure 3 is a top plan view of the fuse indicator of this invention.

As shown on the drawings:

The fuse indicator of'this invention is mounted n a plug 1, which isformed from Insulating material such as hard rubber or fibre. Saidcylindrical plug 1 is provided in substantially the central portionthereof with a peripheral flange 2. The ortion of the plug 1 below theperipheral ange 2 is threaded at 4 and a central aperture 3 is providedthrough the interior of the plug 1. The bottom of the plug 1 iscountersunk at 5 to provide a tapered opening into the central aperture3. The upper edge of the plu 1' is rounded and engaged thereover anresting on the top of the peripheral flange 2 is a domed cylinder 6,which is preferably constructed of mica or other non-inflammabletransparent insulating material. A small central aperture 7 is providedin the upper portion of the domed cylinder 6. The indicating device ofthis invention is adapted to be secured on any form of inclosed fuse. Itis shown in Figure 1 secured in the outer insulating casing 9 of a fuse8 of the knife contact type which is fully described in my pendingapplication for U. S. Letters Patent, SerialNo. 312,343.. This insulatedcasing 9' is apertured preferably near the central portion thereof andthe threaded portion at of the plug 1 is engaged in said aperture. InFigure 2 the indicating deviceof this invention is shown secured in theouter casing 11 of a clip contact type of fuse -which is fully describedin my pending appIlication for U. S. Letters Patent, Serial 0. 312,340.An aperture 12 is provided preferably near the central portion of theouter casing 11 of said fuse 10 and the lower threaded portion 4 of theplug 1 is engaged therein. An aperture 14 is provided in the innerinsulating casing of the fuse 10 directly below the aperture 12 in theouter casing 11 in order that the indicating device of this inventionmay be in communication with the chamber in which the fusible element 15is contained.

The operation is as follows:

The indicating device of this invention is secured in the outer casingof the fuse on which it is to be used b threading the threaded portionof the p ug 1 in an aperbit ing out explosion will affect the indicatingdevice of this invention in various ways. In case of a severe shortcircuit the force of the blowing out'of the fuse will-either blow thedomed cylinder from the plug 1 or crush the cylinder so that the fact ofthe fuse being burned out will be easily discernible from the exteriorof the casing. in case of a slower burning out of the fuse where a lessviolent explosion takes place the transparent domed cylinder 6 will bediscolored in such a manner that an external inspection clearlyindicates that the fuse therein was, damaged. On account of the aperture7 in the top of .the domed cylinder 6, smoke from the burned fuse willissue therefrom for some time after the fuse 15 has burned out. Thus ifan inspector comes into the room within any reasonable time after theburning out of the fuse 17, his attention will be called to the factthat the fuse has burned out by the smokewhich is rising from theaperture 7 in the cylinder 6. It is of course to be understood that theindicating device of this invention may be applied to any type ofenclosed fuse whether removable or rigid and that-it provides aconvenient means for determining whether the fusible element inside theenclosing means is burned out thereby greatly facilitating theinspection of the fused electric circuit.

The inspector or repairman can carry several extra transparentindicating cylinders inorder to replace those that are broken,

- lost, or discolored at the same time the fuse is renewed.

I am aware that numerous details of construction may be varied through awide range without departing from the principles of this invention, andl therefore do not purpose limiting the patent granted otherwise thannecessitated by the prior art.

ll claim as my invention:

1. A fuse indicator comprising an internally apertured'. plug, anexternal flange thereon, and a transparent indicating device engagedover one end of the plug and abutting the flange.

2. A fuse indicator comprising an internally apertured plug, an externalflange thereon, and a transparent indicating cylinder of non-inflammableinsulating material engaged over one end of the plug and abutting thefiange.

3. A fuse, a casing enclosing /said fuse,

said casing having an aperture therein, a tube lining said aperture, anda transparent closure for said tube.

f. A fuse, a 'casing enclosing said fuse, said casing having an aperturetherein, a closure for said aperture, said closure. having an openperforation smaller than the aperture in the casing.

5. A fuse, a casing therefor, said casing having an aperture therein,and a domeshaped member of transparent material secured over saidaperture.

6. Afuse,acasing therefor,a tube through the wall of said casing and adome-shaped closure for the end of said tube, the height of the wall ofthe casing.

7. A fuse, a casing therefor, a tube through the wall of said casing anda dome-shaped closure frictionally mounted on said tube.

of the dome being greater than the thickness 8. A fuse, a cylindricalcasing therefor I having a hole in the side thereof,'a tube screwed insaid hole and countersunk on inner end.

9. A fuse, a cylindrical casing therefor, i

having a hole in the side thereof, a tube screwed in said hole andcountersunk on its inner end, and a dome-shaped cover frictionallymounted on the outer end of said tube.

10. A fuse, a cylindrical casing therefor having a hole in the sidethereof, a tube screwed in said hole and countersunk on its inner end,and a dome-shaped cover on the outer end of said tube, and said domehaving an open hole opposite the mouth of said tu e.

In testimony'whereof l have hereunto subscribed inynarne in the presenceof two subscribing witnesses.

JQHN B. GLUWACKl.

Witnesses:

CHARLES Hrrradr, EARL M. HARDINE;

